JP4016544B2 - Radiator for supercritical vapor compression refrigeration cycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiator (gas cooler) applied to a supercritical vapor compression refrigeration cycle (hereinafter referred to as a supercritical cycle) in which the refrigerant pressure on the high pressure side (discharge side) is equal to or higher than the critical pressure of the refrigerant. is there.
[0002]
[Prior art]
In a vapor compression refrigeration cycle using chlorofluorocarbon as a refrigerant (hereinafter referred to as a subcritical cycle), the pressure on the high pressure side is less than the critical pressure of the refrigerant. Phase change (condensation) from liquid to refrigerant.
[0003]
For this reason, since the refrigerant density increases as the refrigerant advances from the refrigerant inlet side to the refrigerant outlet side of the condenser, the refrigerant inlet is generally formed above the refrigerant outlet. It was.
[0004]
[Problems to be solved by the invention]
By the way, in a vehicle air conditioner, generally, a heat exchanger for cooling such as a condenser or a radiator is mounted on the front side of the vehicle so that cooling air having a low temperature can be easily taken in. .
[0005]
Therefore, the inventors measured the temperature of the cooling air flowing into the cooling heat exchanger such as a condenser or a radiator to improve the cooling capacity of the air conditioner when the vehicle is stopped. It was discovered that the temperature of the cooling air flowing into the lower side of the cooling air is higher than the temperature of the cooling air flowing into the upper side of the cooling heat exchanger.
[0006]
That is, when the vehicle is stopped, as shown in FIG. 10, there is radiation of heat (geothermal heat) from the ground and hot air discharged from the engine room, so cooling that flows into the lower side of the cooling heat exchanger 200 is performed. The wind is heated, and the temperature of the cooling air flowing into the lower side of the cooling heat exchanger becomes higher than the temperature of the cooling air flowing into the upper side of the cooling heat exchanger.
[0007]
Incidentally, according to examinations by the inventors, when the outside air temperature is 40 ° C., about 55 ° C. cooling air flows into the lower side, while about 45 ° C. cooling air flows into the upper side. As is clear from this example, there is a large temperature difference between the upper side and the lower side of the cooling heat exchanger.
[0008]
In view of the above points, an object of the present invention is to improve the cooling efficiency of a refrigerant in a supercritical cycle radiator.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is applied to a supercritical vapor compressor refrigeration cycle in which the pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant. It is a vehicle mounting structure of the heat radiator (200) which cools the high pressure refrigerant | coolant discharged from, Comprising: In the heat radiator (200), the refrigerant | coolant inflow port (240) into which a refrigerant | coolant flows in, and the refrigerant | coolant after heat exchange flow And the radiator (200) is mounted on the vehicle so that the refrigerant outlet (230) is positioned above the refrigerant inlet (240), and the refrigerant inlet (230) The refrigerant flowing into the radiator (200) from the inside of the radiator (200) flows through the radiator (200) from the lower side to the upper side while reducing its temperature without condensing, and then the refrigerant outlet (230) characterized in that it flows out from the
[0010]
As a result, as described above, the temperature of the cooling air flowing in is lower on the lower side of the radiator (200) than on the upper side, but the refrigerant having a higher temperature flows in from the lower side of the radiator (200). Even if the temperature of the wind is high, a sufficient temperature difference can be ensured between the refrigerant and the cooling air, and the cooling efficiency of the refrigerant can be improved.
[0017]
In the invention according to claim 2 , the radiator (200) includes a tube (210) in which a plurality of radiators (200) are arranged in the vertical direction, each extending in the horizontal direction, and a refrigerant flowing therethrough, and the longitudinal length of the tube (210). The header tank (220) that is disposed on both ends in the direction and communicates with the plurality of tubes (210), and the space in the header tank (220) is partitioned into a plurality of spaces. It circulates from the lower side to the upper side while meandering in the radiator (200) .
[0018]
In the invention according to claim 3, the radiator (200) includes a tube (210) in which a plurality of radiators (200) are arranged in the horizontal direction and extend in the vertical direction, and a refrigerant flows therethrough, and the length of the tube (210). It has header tanks (220) that are arranged on both ends in the direction and communicate with a plurality of tubes (210), and the refrigerant circulates in the radiator (200) from the lower side to the upper side. To do.
[0019]
In the invention according to claim 4 , the radiator (200) has one or a plurality of tubes (210) extending from the refrigerant inlet (230) to the refrigerant outlet (240). The tube (210) extends from the lower side toward the upper side while meandering .
[0021]
Incidentally, the reference numerals in parentheses of each means described above are an example showing the correspondence with the specific means described in the embodiments described later.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
In this embodiment, a radiator for a supercritical cycle according to the present invention is applied to a vehicle air conditioner, and FIG. 1 is a schematic diagram showing a vehicle-mounted state of a supercritical refrigeration cycle (vehicle air conditioner). FIG. 2 is a front view of the radiator according to the present embodiment as viewed from the front side of the vehicle.
[0023]
In FIG. 1, reference numeral 100 denotes a compressor that obtains driving force from a vehicle travel engine (not shown) and sucks and compresses refrigerant (in this embodiment, carbon dioxide), and 200 is discharged from the compressor 100. This is a heat radiator that cools the refrigerant by exchanging heat with the high-pressure refrigerant and air (cooling air). Details of the radiator 200 will be described later.
[0024]
300 depressurizes the refrigerant flowing out of the radiator 200 and, based on the refrigerant temperature on the outlet side of the radiator 200, the refrigerant temperature on the outlet side of the radiator 200 so that the coefficient of performance (COP) of the supercritical cycle is maximized. It is a pressure control valve to control. Since the pressure control valve 300 has a function equivalent to that described in Japanese Patent Application No. 8-33962, detailed description is omitted in this specification.
[0025]
Reference numeral 400 denotes an evaporator that evaporates the refrigerant depressurized by the pressure control valve 300 to exert a refrigerating capacity (cooling capacity), and 500 denotes a refrigerant that flows out of the evaporator 400 into a gas phase refrigerant and a liquid phase refrigerant. Thus, the gas-phase refrigerant is allowed to flow out to the suction side of the compressor 100, and at the same time, an accumulator (gas-liquid separation means) that stores excess refrigerant in the supercritical cycle.
[0026]
Next, the radiator 200 according to this embodiment will be described with reference to FIG.
[0027]
A plurality of tubes 210 are arranged in a row in the vertical direction, each of which extends in the horizontal direction and through which a refrigerant flows. The tubes 210 are extruded or drawn as shown in FIG. As a result, a plurality of refrigerant passages 211 through which the refrigerant flows are formed. And the heat exchange core 213 which cools a refrigerant | coolant is comprised by the wavy fin 212 arrange | positioned between the tube 210 and the tube 210. FIG.
[0028]
In addition, a header tank 220 communicating with a large number of tubes 210 is disposed on both ends in the longitudinal direction of the tube 210, and a space in the header tank 220 is divided into a plurality of spaces by a partition plate (separator) 221. It is partitioned.
[0029]
A refrigerant inlet 230 into which the refrigerant discharged from the compressor 100 flows is formed on the lower side of the header tank 220 (heat radiator 200). On the other hand, on the upper side of the header tank 220 (heat radiator 200), A refrigerant outlet 240 is formed through which the refrigerant after heat exchange flows out. For this reason, the refrigerant | coolant which distribute | circulates the inside of the heat radiator 200 distribute | circulates from the downward side to the upper side, meandering in the heat radiator 200, as shown by the arrow of FIG.
[0030]
Next, features of the present embodiment will be described.
[0031]
In this embodiment, the refrigerant inlet 230 is formed on the lower side of the header tank 220 (heat radiator 200), and the refrigerant outlet 240 is formed on the upper side of the header tank 220 (heat radiator 200). In the state, the refrigerant outlet 230 of the radiator 200 is located above the refrigerant inlet 240.
[0032]
On the other hand, in the supercritical cycle, the refrigerant on the high pressure side (in the radiator 200) flows from the refrigerant inlet 230 side toward the refrigerant outlet 240 side while reducing its temperature without condensing (phase change). Therefore, the refrigerant temperature on the refrigerant inlet 230 side becomes higher than the refrigerant temperature on the refrigerant outlet 240 side.
[0033]
Here, as described above, the temperature of the cooling air flowing in is lower on the lower side of the radiator 200 than on the upper side, but in this embodiment, the refrigerant having a higher temperature flows from the lower side of the radiator 200. Even if the temperature of the cooling air is high, a sufficient temperature difference can be ensured between the refrigerant and the cooling air.
[0034]
Therefore, since the cooling efficiency of the refrigerant can be improved in the radiator 200 of the supercritical cycle, the cooling capacity (refrigeration capacity) of the air conditioner (supercritical cycle) can be improved.
[0035]
Incidentally, the solid line A-B-C-D in FIG. 4 is a diagram showing the supercritical cycle behavior according to the present embodiment, and the broken line E-F-G-H in FIG. 4 shows the refrigerant from the upper side to the lower side. It is a diagram which shows the behavior of the supercritical cycle at the time of distribute | circulating. As is clear from this figure, according to the present embodiment, the refrigerating capacity (the enthalpy difference between CD) is higher than the refrigerating capacity of the conventional supercritical cycle (the enthalpy difference between GH) ( It can be seen that it has increased by about 18%.
[0036]
Note that the present embodiment is not limited to the radiator 200 as shown in FIG. 2, and as shown in FIG. 5, the number of the partition plates (separators) 221 is reduced to turn the refrigerant in the radiator 200. The number may be reduced.
[0037]
Naturally, the number of turns may be increased by increasing the number of partition plates 221 with respect to the radiator 200 shown in FIG.
[0038]
(Second Embodiment)
In the first embodiment, the tube 210 is disposed so as to extend in the horizontal direction. However, in the present embodiment, as shown in FIG. Is distributed from the lower side toward the upper side.
[0039]
(Third embodiment)
In this embodiment, as shown in FIGS. 7 and 8, the header tank 220 is eliminated and the tube 210 itself is meandered to constitute a heat exchange core 213. Incidentally, FIG. 7 shows one tube 210 meandering from the refrigerant inlet 230 to the refrigerant outlet 240, and FIG. 8 shows a plurality (two in this embodiment) of the tubes 210 in the refrigerant inlet 230. To the refrigerant outlet 240.
[0040]
( Reference example )
In the first embodiment, since the refrigerant flows from the lower side toward the upper side against gravity, the flowability of the refrigerant deteriorates, and the distribution property of distributing the refrigerant from the header tank 220 to each tube 210 may deteriorate. There is sex.
[0041]
Therefore, in this reference example , as shown in FIG. 9, the refrigerant inlet 230 is provided on the upper side of the radiator 200 (header tank 220), and the refrigerant outlet 240 is provided on the lower side of the radiator 200 (header tank 220). By providing the refrigerant, the refrigerant flows from the upper side toward the lower side, and the tube cross-sectional area (diameter dimension of the refrigerant passage 211) of the tube existing on the upper side among the plurality of tubes 210 is present on the lower side. Is larger than the cross-sectional area (diameter dimension of the refrigerant passage 211).
[0042]
Thereby, while being able to distribute | circulate many refrigerant | coolants to the upper side of the heat radiator 200 with the low temperature of cooling air, and the temperature difference between an air conditioning wind and a refrigerant | coolant can be enlarged, the heat radiator of a supercritical cycle In 200, it is possible to improve the refrigerant distribution efficiency while improving the cooling efficiency of the refrigerant.
[0043]
In this reference example , the cross-sectional area of the tube existing on the upper side of the plurality of tubes 210 is made larger than the cross-sectional area of the tube existing on the lower side. The number of refrigerant passages 211 in the tubes existing on the side may be larger than the number of refrigerant passages 211 in the tubes existing on the lower side.
[0044]
(Other embodiments)
In the above-described embodiment, the supercritical cycle using carbon dioxide as a refrigerant is used. However, for example, the present invention can also be applied to a refrigerant used in a supercritical region such as ethylene, ethane, and nitrogen oxide.
[Brief description of the drawings]
FIG. 1 is a schematic view of a vehicle equipped with a radiator according to a first embodiment of the present invention.
FIG. 2 is a front view of the radiator according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view of the tube of the radiator according to the first embodiment of the present invention.
FIG. 4 is a ph diagram of carbon dioxide.
FIG. 5 is a front view showing a modification of the radiator according to the first embodiment of the present invention.
FIG. 6 is a front view of a radiator according to a second embodiment of the present invention.
FIG. 7 is a front view of a radiator according to a third embodiment of the present invention.
FIG. 8 is a front view showing a modification of the radiator according to the third embodiment of the present invention.
FIG. 9 is a front view of a radiator according to a reference example .
FIG. 10 is an explanatory diagram for explaining a problem of a conventional technique.
[Explanation of symbols]
200 ... radiator, 210 ... tube, 220 ... header tank,
230 ... refrigerant inlet, 240 ... refrigerant outlet.

Claims (4)

A vehicle-mounted structure of a radiator (200) that is applied to a supercritical vapor compressor refrigeration cycle in which the pressure on the high-pressure side is equal to or higher than the critical pressure of the refrigerant and cools the high-pressure refrigerant discharged from the compressor (100). ,
The radiator (200) is formed with a refrigerant inlet (240) into which refrigerant flows in and a refrigerant outlet (230) through which the refrigerant after heat exchange flows out,
The radiator (200) is mounted on a vehicle such that the refrigerant outlet (230) is positioned above the refrigerant inlet (240) ,
The refrigerant flowing into the radiator (200) from the refrigerant inlet (230) circulated from the lower side to the upper side while reducing the temperature without condensing. A structure for mounting a radiator on a vehicle, which flows out from the refrigerant outlet (230) later . The radiator (200) includes a tube (210) in which a plurality of the radiators (200) are arranged in the vertical direction, each extending in the horizontal direction, and in which a refrigerant flows.
A header tank (220) disposed on both ends in the longitudinal direction of the tube (210) and communicating with the plurality of tubes (210);
The space in the header tank (220) is partitioned into a plurality of spaces, so that the refrigerant flows from the lower side to the upper side while meandering in the radiator (200). Item 1. A radiator mounting structure for a radiator according to Item 1. The radiator (200) has a plurality of tubes arranged in the horizontal direction, each extending vertically and a tube (210) through which a refrigerant flows,
A header tank (220) disposed on both ends in the longitudinal direction of the tube (210) and communicating with the plurality of tubes (210);
The vehicle-mounted structure of a radiator according to claim 1, wherein the refrigerant flows through the radiator (200) from the lower side toward the upper side. The radiator (200) has one or more tubes (210) from the refrigerant inlet (230) to the refrigerant outlet (240),
The vehicle mounting structure for a radiator according to claim 1, wherein the one or more tubes (210) extend from the lower side to the upper side while meandering.

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